import Outputable
import FastString
-import qualified Data.Foldable as Foldable
-import Data.Functor( (<$>) )
import Data.List( mapAccumL )
import Data.IORef
\end{code}
-- A TauTv is always filled in with a tau-type, which
-- never contains any ForAlls
- | SigTv Name -- A variant of TauTv, except that it should not be
+ | SigTv -- A variant of TauTv, except that it should not be
-- unified with a type, only with a type variable
-- SigTvs are only distinguished to improve error messages
-- see Note [Signature skolems]
-- The MetaDetails, if filled in, will
-- always be another SigTv or a SkolemTv
- -- The Name is the name of the function from whose
- -- type signature we got this skolem
| TcsTv -- A MetaTv allocated by the constraint solver
-- Its particular property is that it is always "touchable"
\begin{code}
pprTcTyVarDetails :: TcTyVarDetails -> SDoc
-- For debugging
-pprTcTyVarDetails (SkolemTv _) = ptext (sLit "sk")
-pprTcTyVarDetails (RuntimeUnk {}) = ptext (sLit "rt")
-pprTcTyVarDetails (FlatSkol {}) = ptext (sLit "fsk")
-pprTcTyVarDetails (MetaTv TauTv _) = ptext (sLit "tau")
-pprTcTyVarDetails (MetaTv TcsTv _) = ptext (sLit "tcs")
-pprTcTyVarDetails (MetaTv (SigTv _) _) = ptext (sLit "sig")
+pprTcTyVarDetails (SkolemTv {}) = ptext (sLit "sk")
+pprTcTyVarDetails (RuntimeUnk {}) = ptext (sLit "rt")
+pprTcTyVarDetails (FlatSkol {}) = ptext (sLit "fsk")
+pprTcTyVarDetails (MetaTv TauTv _) = ptext (sLit "tau")
+pprTcTyVarDetails (MetaTv TcsTv _) = ptext (sLit "tcs")
+pprTcTyVarDetails (MetaTv SigTv _) = ptext (sLit "sig")
pprUserTypeCtxt :: UserTypeCtxt -> SDoc
pprUserTypeCtxt (FunSigCtxt n) = ptext (sLit "the type signature for") <+> quotes (ppr n)
go (ForAllCo tv co) = ForAllCo tvp $! (tidyCo envp co)
where
(envp, tvp) = tidyTyVarBndr env tv
- go (PredCo pco) = PredCo $! (go <$> pco)
go (CoVarCo cv) = case lookupVarEnv subst cv of
Nothing -> CoVarCo cv
Just cv' -> CoVarCo cv'
-- not a SigTv
= ASSERT( isTcTyVar tv)
case tcTyVarDetails tv of
- MetaTv (SigTv _) _ -> False
- _ -> True
-
+ MetaTv SigTv _ -> False
+ _ -> True
+
isSkolemTyVar tv
= ASSERT2( isTcTyVar tv, ppr tv )
case tcTyVarDetails tv of
isSigTyVar tv
= ASSERT( isTcTyVar tv )
case tcTyVarDetails tv of
- MetaTv (SigTv _) _ -> True
- _ -> False
+ MetaTv SigTv _ -> True
+ _ -> False
metaTvRef :: TyVar -> IORef MetaDetails
metaTvRef tv
orphNamesOfCo (TyConAppCo tc cos) = unitNameSet (getName tc) `unionNameSets` orphNamesOfCos cos
orphNamesOfCo (AppCo co1 co2) = orphNamesOfCo co1 `unionNameSets` orphNamesOfCo co2
orphNamesOfCo (ForAllCo _ co) = orphNamesOfCo co
-orphNamesOfCo (PredCo p) = Foldable.foldr (unionNameSets . orphNamesOfCo)
- emptyNameSet p
orphNamesOfCo (CoVarCo _) = emptyNameSet
orphNamesOfCo (AxiomInstCo con cos) = orphNamesOfCoCon con `unionNameSets` orphNamesOfCos cos
orphNamesOfCo (UnsafeCo ty1 ty2) = orphNamesOfType ty1 `unionNameSets` orphNamesOfType ty2